Jointer for concrete roads



2 ksn lSBMILLER JOINTER FOR CONCRETE ROADS Filed Jan. O, 1922 j /nnnnnnnnnnnnnn HnuuUHUU-ulJl-luuuuuuyvuuuuuu ooqooooooooooooo'ooooooooooooo Feb. i3', 1923.

INVENTOR.

Patented heb, I3, i923.

UNITS@ i? T if l9445g229y SHREWSBURY B. MILLER, OF FAIBIIIONT, WEST VIRGINIA.

JGIN'IER FOB CONCRETE ROADS.

Application iled January 20, 1922.

To all 'whom t may concern:

Be it known that I, SHnnwsnUnY B. MILLER, a. citizen ot the United States, residing at Fairmont, in the county of Marion and State of 1West Virginia, have invented a new and useful Jointer 'for Concrete Roads, of which the 'following is a specification.

My invention relates to improvements in forming a joint or line of weakness in a concrete slab, such as a concrete road, along which line the concrete will crack or separate, sometime after the slab has hardened and become set, when stressed by shrinkage strains. It has been my observation and become my belief that concrete roads shrink more than expand, and that contraction always takes pla-ce first, therefore, I provide a.

contraction crack that will subsequently allow for expansion, and that no expansion joint with asphaltic filler is necessary.

By using my method for dividing a length ot concrete road into any desired number of sections to take care of the contraction, in the future, the use ol' other joints in the concrete is made unnecessary, with a consequent saving in time and expense in laying the concrete. I attain my object by imbedding in the concrete a transverse line ot pins or plugs that may be of wood, for example, these pins may have any diameter and olE a length to suit the depth of the concrete and as the pins are introduced while the concrete is green or un-set the operation is simple.

It is obvious that this line ot pins will weaken the strength of the concrete along this line, lbecause the section of the concrete on this line is less than along some other line where the concrete is olf 'full section. And that when shrinkage stresses appear in the concrete the stresses will be relieved by the concrete separating or cracking along this predetermined line, which line will be straight and the crack vertical, beca-usel the pins will be set vertically. l

To attain the objects of my invention I use the appliances and attributes illustrated in the accompanying` drawings:

'l is a plan view o'li a bar having a length to correspondwith the width of the concrete road being constructed, the bar in all views in the drawing being designated (l) along the length of the bar are set the guides (2) at such intervals as may be desired, with handles (3) for lifting and placing the bar.

Serial N0. 530,730.

F ig. 2 shows the bar in side view with guides (2) andy handles (3). y

Fig. 3 is a plan View of a slab of concrete showing the pins (4) located transversely across the slab, and along which line of pins it is intended the concrete shall open when contraction stresses are set up in the slab.

Fig. 4 is a section. of the bar (l) on a plane through a. guide (2) showing the pin (4) with pointed end (8) about to be introduced in to the guide (2) also the guide (2) extends above the bar a distance (6) and below the bar a distance (5) the lower surface (7) of the bar rests in the concrete surface of the slab. y f

Fig. 5 shows the follower (8) with handle (9) for the purpose of setting the pins the distance (5) below the concrete surace.

Fig. 6 shows a transverse section of a concrete road into which the pins (4) have been set, in the vertical plane in which it is in* tended the slab shall crack when contraction in the slab takes place.

The operation of my jointer is as follows:

ritter the concrete road surface has been struck to the required contour, the jointer is placed in position near the end of the concrete being placed, and where the section of concrete is full and where bar can be reached lto :insert the pins without. disturbing 'the placed concrete. Then the required number of pins (4) are placed in the guide (2) and driven into the green concrete to the top of the guide (2). rIhe pin set is then used and the pin driven into the concrete as tar as In testimony whereof I hereunto atlix my signature in the presence of two witnesses.

SI-IREWSBURY B. MILLER.y

Witnesses EDWARD CRowL, M. Norret. 

